Pigtail connection.



W. SHAW.

PIGTAIL CONNECTION.

APPLICATJQN FILED OCT. 15, 1912.

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WITNESSES IJNVENTOB ATTORNEY sTA'rEs rrnnr on ICE.

WILLIAM SHAW, OF LAKEWOOD, OHIO, ASSIGNOR TO CARBON COMPANY, OF

' CLEVELAND, OHIO, A CORPORATION OF OHIO.

PIGTAIL CONNECTION.

Specification of Letters Latent.

Patented July 20, 1915.

Application filed October 15, 1912. Serial No. 725,850.

clear and exact description.

This invention relates to connections for brushes on dynamo-electricmachines commonly called pigtail connections.

the invention is to secure One object of h the brush with minimum theconductor to contact resistance.

Another object is to secure the conductor to the brush so that it cannotwork loose in practice, but to attach it in such a manner that it can bereadily removed, and attached to another brush when. the first one is nolonger serviceable;

Other objects will appear in the appended description.

In the drawings: Figure 1 is a section of a-spun tube from which clipsare made. Fig. 2 is a View of the clipatter the pigtail has beeninserted in the tube shown in Fig. 1 and compressed. Fig. 3 is a. topview of the connection shown in Fig. 2. Fig. 4 is a modified form otclip. Fig. 5 is a View of a brush before the pigtail is attached. Fig. 6is a view of the brush with the clip shown in Fig. 3 attached thereto.Fig. 7 is a view of a brush with the clip shown in Fig. i attachedthereto. Fig. 8 is a section on the plane AA of Fig. i}. Fig. 9 is aview of a modified form of brush before the pigtail'is connectedthereto. Fig. 10 is a view of the brush shown in Fig. 9 with the pigtailattached. Fig. 11 is a section taken on the line BB of Fig. 10. Fig. 12is a View of the nut used to clamp the pigtail in Fig. 10. Fig. 13 is amodified form of connection. Fig. 14 is a section of a slightlydifferent form.

Referring to Fig. 1, if a section of a tube 1 be spun down at one end asat 2, a conductor inserted through the reduced opening, and the tube.pressed together, an attractive and serviceable clip results. A sideview of the clip and pigtail is shown in Fig. 2. A hole 3] is formedthrough the clip, Fig. 3, and the same is threaded to receive-a screw.The method of making this new form of clip is described in myapplication filed Aug. (3, 1912, Serial No. 713,571, and hence themanner in which it is made is given in this application only in a briefway. This form of clip is easily made and gives a very attractive strongconnection. It might seem that if a hole were threaded through such aclip that it would not be strong enough to serve as a nut to clamp theconnection to the brush, but it has been found that the clip will serveas a nut and makes a strong connection. The small wires of the pigtailwhich are compressed between the sides seem to be rigidly held inplaceso that they help form the threads.

A brush 4, Fig. 5, has a hole 5 formed through it and a channel or slot6 is formed shown. This channel is cut to such a depth that the clipplaced in it is approximately flush or beneath the surface of the brush;so as to prevent the connection from interfering with the movement ofthe brush in the holder. The clip 5 with the attached conductor isplaced in the slot 6, Fig. 8, and drawn firmly against the brush by thescrew (3. The screw may be locked in place if desired by the bail 7which tits in the slot in the screw head. The lock may in some cases beomitted. The slot (3 need not necessarily extend to the top of the brushparallel o. its sides. It may extend diagonally toward the top corner ofthe brush.

In some types of brushes a separate metallic piece is extended over thetop of the brush to serve as a rest for the spring hammer that forcesthe brush against the commutator. My new form of clip can be made toserve both as the nut and as the hammer rest bymaking it of suitablelength and bent to extend part way or entirely across the top oi thebrush. Such a clip is shown in Fig. 4 and shown connected to the brushin Fig. 7. This arrangement gives additional contact surface as the topportion 8 of the clip engages the top of the brush. In this form, aswell as that shown in Fig. (3, the shape of the clip is non-circular sothat it cannot work loose. The bail 7 serves to prevent the screw fromturning so that the connection is securely locked. WVhen the brush isworn'out the bail may be pulled out or the brush may be broken apart.The screw can then be disengaged from the nut and the connection placedon another brush.

In Figs. 9, 10 and 11, I have shown a modified form of connection. Thepigtail end in this case is not secured to a clip, but

is coiled around the screw 6 in a groove and tightly compressed thereinby an angular shaped nut 10. The nut extends over the top of the brushand serves as ahammer support and furnishes additional contact surfaceto take the current from the brush. .The prolongation of the nut alsoserves to eil'ectively prevent the nut from turning. The pigtail mayextend through the groove or it may extend up through a straight slottedbrush as in Fig. 5, and pass through a hole or notch 12 in the nutextension as in Fig. 13.

If desired the groove 9 may be omitted and the igtail clamped by the nut10 against the flat bottoin of the slot as in Fig. 14. I prefer,however, the arrangement shown in Fig. 9 asthe wires 1-3 are compressedin the groove 9 and give elasticity to the connection such that anexpansion of the screw or other loosening will not destroy the goodcontact. This grooveiis preferably convergent as shown, though'on'e sideneed not necessarily be vertical. The elastic eibe limited to any formof pigtail, but is intended to include all forms of flexible conf vductors.

Having described my invention What I claim is:

1. In a current collector, a brush having a and such'coatscrew fromturning.

hole therethrough terminating ma channel,

said channel extending .toth'e top of the brush, a nut inthe channel.and a screw in said-hole'engaging thetnut, said nut having aprolongation extending; over the top of the brush, and a igtail fastenedto the prolongation. I

i 2. In a currentcollector, a brush having a hole therethrough, a nuthaving a prolongation extending over the top of the brush, a screw insaid hole engaging the nut and a igtail fastened to the prolongation.

3. In a current collector, a brush having a channel in one side, acurrent connection consisting of a clip. compressed around a strandedconductor, said connection having a hole therethrough with threads cutin the clip and strands of said conductor, a screw extending through thebrush and,sec'uredin said threaded hole to retain the clip in thechannel.

'4. In a current collector, a brush having a channel in one side, acurrent connection consisting of a clip compressed around a strandedconductor, said connection having a hole therethrough with. threads cutin the clip and" strands oi said conductor, a screw extending, throughthe brush and secured in the threaded hole to clamp the clip in saidchannel, d a. bail in the slot of thescrew head ext K into the brushtogreventthc In testimony Wl'lQIQOf I have hereunto sig ed my name.WILIJAM snA-w'. Witnesses r E. M. SPELMAEY, L. 0. B12007

